The invention relates generally to a method to map a set of biomarker images acquired by a fluorescent microscope into a new color space where the mapped image intensity values represent a brightfield modality.
In traditional histological staining with Hematoxylin & Eosin (H&E), the basophilic dye Hematoxylin (H) is used to stain the cell nuclei blue, and the acidophilic dye Eosin (E) is used as a counter-stain to stain cytoplasm, connective tissue (collagen), muscle fibers, connective tissue, and red blood cells. Eosin interacts with different cellular components in the tissue producing different shades of pink color based on charge properties of the molecules to which eosin is binding. These cellular components can be alternatively labeled using molecular markers (dyes and antibodies) with fluorescent dyes. For example, cell nuclei can be stained with DAPI (a fluorescent dye that binds DNA specifically) while other regions in the tissue can be labeled immunofluorescently where the molecules of interest are targeted by directly conjugated antibodies, or by primary secondary amplification detection. For some structures, such as red blood cells (RBC), tissue autofluorescence captured by a set of filters can be used for detection. Fluorescent imaging modality has the advantage of capturing each of these tissue structures individually, hence enabling accurate localization and quantification.
However, histopathological diagnosis based on fluorescent images is not a common practice because fluorescent images do not provide structural and morphological details that are essential for pathologists to diagnose. Brightfield H&E staining techniques are also often favored because there exists a large body of knowledge about these techniques, assembled for decades in pathology laboratories.
A method of transforming fluorescent images into a color domain that resembles brightfield images, such as H&E is desirable to allow pathologists to perform both quantitative analysis as well as pathologic diagnostics on the same set of fluorescent images.